Abstract: Abstract: In recent years, under the dual pressures of labor and mechanization, the demand for gardening equipment in the facility is increasing in China. Especially the nursery part has the heavy workload, and there is the most urgent demand for automatic production equipment. Pick-up mechanism is a key part of most nursery production equipment, the pneumatic pick-up is a flexible clamping technology, and it is developed for the seedling clamping job in recent years, but the existing flexible pneumatic pick-up method is based on a rigid platform to pick up seedlings. Because there are individual differences of seedlings, the existing pick-up mechanism is difficult to adapt to the changes of seedlings size and morphology, which results in the stationary adsorption distance that makes it difficult to adsorb all the seedlings on the rigid platform. In the pick-up operation, the negative pressure sucker is set to contact with the seedlings, but the seedlings with true leaves on the rigid platform are not kept at the horizontal state, which will lead to the problems of being difficult of adsorbing seedlings, long operating time, and consuming energy. To solve the above problems, based on vacuum adsorption principle, the study comes up with a flexible pneumatic pick-up method for seedlings. The method is constituted by the negative pressure pick-up finger and flexible seedling seat. The flexible seedling seat designed in this study consists of the plate to put seedling, the buffering steel cable and the fixing plate. The eggplant seedlings are manually placed on the plate with the V-notch, so the eggplant seedlings are limited by the V-notch in the diameter direction. The flexible seedling seat has a certain height, and the seedlings is in the horizontal state on the buffering steel cable, thus solving the problem that the pick-up operation is unstable because it is one end high and one end low for the seedlings due to the existence of the true leaves. At the same time the seedlings are supported by the buffering steel cable. The seedlings on buffering steel cable can avoid rigid extrusion when they are on the rigid platform. By the stress analysis, buffering steel cable diameter is calculated to be 0.32 mm. Because the maximum leaf span is 100.3 mm, the height of seedling seat is designed as 50 mm. In summary, the flexible seedling seat is better than the rigid platform on locating seedlings. The flexible seedling seat can correct the seedling place position. Because of the buffering effect of the flexible seedling seat, it can resolve the problem that the rigid platform is difficult to adapt to the size and morphology of seedlings. On this basis, the experiment is performed to optimize the structural parameter of flexible seedling seat. And the comparison test of the pick-up performance between the rigid platform and the flexible seedling seat is carried out. Test shows that: The support spacing between 2 buffering steel cables of the flexible seedling seat is 9 mm, the notch depth to holding seedling is 6 mm, and the side distance between the fixation point of buffering steel cable and the plate is 4 mm. At the above conditions, the adsorption pick-up success rate can be guaranteed to be over 90% within 2.8-5.1 mm range for eggplant seedlings. On the base of absorbing eggplant seedlings scion successfully with the diameter of the seedling of 4 mm (the diameter of the seedling between 3.8 to 4.2 mm also is classified as the diameter 4 mm), when it is on the rigid platform, the average seedling injury rate is 21%, the average response time for the adsorption is 0.08 s; when it is on the flexible seedling seat with the best combination of structural parameters, the average seedling injury rate is 5%, which is decreased by 16% compared with the rigid platform, the average adsorption response time reduces to 0.03 s, and the productivity increases by 62.5% compared with that on the rigid platform. The findings will provide an important reference for the development of picking device for agricultural robot.